Retentive memory on Micrologix 1100

Hello, I need use retentive memory in a Rockwell Micrologix 1100 to save the value of some variables and the state of some counters when the power of the PLC is lost. How can I do? Must I use some special instructions? If I use a memory module, can I resolve my problem? In that case, all the temporaly data of my program will be retentive?

Thanks.

I have never had an issue with Counter data being lost when powering down a ML1100. I think all the counter values will remain, without any special instructions. Same with Integer, Double Int, Floats, etc. Unless something else copies data to them on something like the First Scan bit, powering down and powering up will not change the data.